This research is an investigation of the dynamic processes governing the behavior of oligopeptides in field desorption ion sources in an attempt to develop FD mass spectrometer techniques which can effectively contribute to the structural elucidation of peptides isolated from biological sources. A specific objective is to apply the procedures developed to the analysis of newly isolated, peptidic hypothalamic hormones. Three principal problems associated with FDMS analysis of peptides have been identified in the literature: (1) difficulty in determining whether the observed peak is a molecular ion (M) of a quasi-molecular ion (M 1); (2) difficulty in accounting for solvent effects; and (3) difficulties with inorganic impurities which accompany a sample. These problems reflect the lack of an adequate conceptual understanding of the processes occurring on an FD ion source. A series of fundamental experiments on the field desorbtion analysis of oligopeptides are proposed which may reveal the nature of the processes governing ionization and allow better characterization of the ions produced. Specific objectives of these experiments include the following: (1) investigate and identify for various emitter geometries the processes governing the transport and ionization of peptides; (2) investigate and identify the effects of specific chemical and physical variables on the structure of peptide mass spectra; and (3) develop and evaluate an experimental protocol for the analysis of natural peptide samples.